Screen Basket with Replaceable Profiled Bars

ABSTRACT

A screen basket with replaceable profiled bars and method of making such screen basket are described herein. The screen basket includes profiled bars evenly spaced circumferentially to form a plurality of continuous slots that covers the whole basket length. The profiled bars are fixed in place by a backing structure, including support rings. In pulp and paper industry, this type of basket is mainly used for pulp screening and is commonly referred to as wedge wire basket. As opposed to conventional wedge wire baskets, in which the profiled bars are permanently joined to the rings, the present invention allows replacing the profiled bars when required and to fully re-use the main structural elements. This is achieved with an assembly that allows to insert the profiled bars, preferably consecutively sled into each aligned ring grooves in a vertical movement. The ring grooves are profiled such that there is sufficient clearance for sliding in the profiled bars. The mounting clearance is then removed radially to hold the profiled bars in place. According to an illustrative embodiment, this is achieved by squeezing an element made of compressible material, and placed between each ring pair.

FIELD OF THE INVENTION

The present invention relates to screen baskets used for screening fibersuspensions, and more particularly to a screen basket which can beapplied in the pulp and paper industry, for example in pressure screenapplications. The innovations of the present invention can also beadvantageously applied for basket manufacturing used for screw pressesor other filtration or dewatering devices.

BACKGROUND OF THE INVENTION

Pulp screening in the pulp and paper industry is generally achieved withpressure screens in which the furnish is pumped to remove oversizedcontaminants, fiber bundles, wood fragments, and/or sort long and shortfibers, and/or stiff and soft fibers. Several pressure screenconfigurations are in use today. The two main configurations arepressure screens using substantially cylindrical outward flow basket,and screens using substantially cylindrical inward flow basket. All thepressure screens generally require the accepted stock to pass throughthe holes or slots of a screen basket. Rejects too large to pass throughthe screen basket or wedge-wire basket openings leave through a rejectsoutlet. A rotor is used to prevent the slots or holes from plugging. Therotor creates pressure pulsations resulting in sufficient cleaningaction of the screening surface to avoid plugging condition.

In applications with aggressive rotor, screen baskets are subjected tohigh dynamic loading from the pressure pulsations generated by therotor. In such applications, ring fatigue failure of wedge wire basketis commonly observed and the mills are often forced to get back tomilled slot or drilled baskets, resulting in a loss of capacity and/orefficiency for obtaining acceptable screen basket life.

Wedge wire baskets are most commonly welded assemblies. Baskets fromthese constructions suffer to various degrees from distortion, residualstress, stress concentration from welded joint geometry and welddefects, which can normally be associated with most welding processes.

Among the screen baskets commercially available, the wedge wire basketsare the ones offering the highest open area because of their continuousslots extending over the entire basket length. The accuracy of the colddrawing process used in wire manufacturing can be advantageously used toachieve exceptionally accurate slot width and highly repeatable contourgeometry, which contribute in providing better efficiency and capacitythan milled slot or drilled baskets.

Conventional wedge wire screen baskets generally comprise a plurality ofwedge wires (profiled bars) that are permanently joined to support ringsby various methods. It should be understood by the term “permanentlyjoined” that a destructive method, such as cutting, grinding, chemicalattack, etc., would be required to remove the profiled bars. Supportrings are necessary to withstand the loading to which the basket issubjected during screening. For severe applications, the screen basketare often reinforced using additional welded or shrink fit rings orbacking jacket.

Some efforts have been made by manufacturers to re-use a portion of themain structure by using replaceable screening elements. However, themanufacturing of these elements is costly and requires several steps andmore material at each rebuild. Also, loss in open area is sometimesgenerated because of the fixing devices such as cage or backing jacket.Finally, the slot and contour accuracy and uniformity are alsocompromised because of the assembly method. An example of a wedge wirescreen basket which has its main structure re-use can be seen inInternational Patent Application no. WO 02/083263 A1, published on Oct.24, 2002, naming Lutz et al. as the inventors and titled “ScreenCylinder and Method”.

U.S. Pat. No. 5,791,495, issued to Gero et al. on Aug. 11, 1998 andtitled “Paper Pulp Screen Cylinder” describes a basket made with milledbars to obtain a basket with replaceable profiled bars. However, theproposed basket is not provided with continuous slots over the entirebasket length, which compromises its capacity. Also, the manufacturingof the profiled bars adapted for the proposed screen basket requiresadditional steps, such as milling, cutting, and machining. Furthermore,the quantity of parts to be assembled becomes very high because each rowrequires a set of milled bars.

U.S. Pat. No. 6,051,103 issued to Aikawa on Apr. 18, 2000 and titled“Paper-Making Screen Apparatus” concerns an inward-flow screen basketprovided with both replaceable bars and continuous slots. A drawback ofAikawa's basket is that a minimum clearance has to be provided betweenthe rod-shaped members and the engaging sections of the support membersto allow insertion of the rod-shaped members therein. This clearance maycause the movements of the rod-shaped members in the engaging sectionsduring operations and even vibrations, which in turn can cause fatigueand premature wear of the parts.

OBJECTS OF THE INVENTION

An object of the present invention is therefore to provide an improvedscreen basket.

Another object of the invention is to provide a demountable screenbasket having replaceable profiled bars which can be locked in place.

SUMMARY OF THE INVENTION

More specifically, in accordance with a first aspect of the presentinvention, there is provided a screen basket comprising:

a plurality of profiled bars generally aligned along a longitudinal axisso as to define a slotted cylindrical wall having an inner side and anouter side extending between two longitudinal ends; each of the profiledbars having a radial profiled portion and a radial locking portionjoined at an intermediate cross-section; the radial locking portionhaving an irregular cross-section including at least one radialcross-section wider than the intermediate cross-section; and

a plurality of support ring assemblies, each removably mounted to atleast some of the plurality of profiled bars for assembling theplurality of profiled bars into the slotted cylindrical wall; each ofthe plurality of support ring assemblies including a stack of first andsecond annular support rings; at least one of the first and secondsupport rings including a plurality of grooves; each groove beingconfigured and sized for complementary receiving the radial lockingportion of a respective one of the profiled bars; the first and secondsupport rings being mounted to each other and to the plurality ofprofiled bars so as to yield a locking force towards the radial lockingportion of the profiled bars, thereby locking the profiled barsthereonto.

According to a second aspect of the present invention, there is provideda method for assembling a screen basket comprising:

providing a plurality of support ring assemblies including first andsecond support rings; at least one of the first and second support ringsincluding a plurality of grooves;

providing a plurality of profiled bars, each having a radial profiledportion and a radial locking portion joined at an intermediatecross-section; the radial locking portion having an irregularcross-section including at least one radial cross-section wider than theintermediate cross-section; the radial locking portion being configuredfor complementary insertion into one of the grooves of first and secondsupport rings;

inserting the locking portions of the profiled bars into the grooves ofthe first and second support rings so as to generally align the profiledbars along a longitudinal axis and to define a slotted cylindrical wallhaving an inner side and an outer side extending between twolongitudinal ends; and

applying a locking force towards the radial locking portion of theprofiled bars for releasably locking the profiled bars in the supportring assemblies.

It is to be noted that the magnitude of the locking force is such thatit is several times that generated by pressure differential and pressurepulsations from the rotor of the apparatus into which the screen basketis used, which prevents movement of the profiled bar during normaloperation.

One of the benefits of the present invention is that it provides abasket assembly for which the profiled bars and other parts thereof canbe replaced. Some other benefits that also substantially improve screenbasket technology are:

-   -   The profiled bar assembly does not require any welding. This        provide substantial increase of the profiled bar fatigue        strength since it avoids detrimental conditions that can be        created in a welded assembly (notches, cracks, distortion,        residual stresses, metallurgical problems, etc.).    -   The profiled bars are integral, i.e. the assembly does not        require any hole that would weaken the bars.    -   No forming stress is present in the rings since they are cut        round from plate before assembly.    -   The present screen basket can be adapted for both inward flow        and outward flow basket configurations.    -   The present screen basket can also be used advantageously for        conical screens or open shape panels such as flat screens,        curved section screens, or any imaginable and practical shapes        of screens using bar assembly.

A screen basket according to the present invention is not limited to thepaper or pulp industry. It can also be used in other industries usingprofiled bars to generate a plurality of screening, draining, filtering,classifying or sorting slots such as but not limited to mining,petrochemical, food and beverage, and water treatment industries, invarious forms and configurations of screening surface (cylinders, curvedsectors, flat sections, etc.). It can further be used in themanufacturing of special drainage rolls.

Other objects, advantages and features of the present invention willbecome more apparent upon reading the following non restrictivedescription of illustrated embodiments thereof, given by way of exampleonly with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the appended drawings:

FIG. 1 is a perspective view of a demountable screen basket according toa first illustrated embodiment of the present invention;

FIG. 2 is a perspective partly sectional view of FIG. 1;

FIG. 3 is a partial close-up view illustrating the assembly of supportring assemblies and profiled bars from FIG. 1;

FIGS. 4A-4B are isolated radial cross-sections of the assembly of onesupport ring assembly and profiled bars from FIG. 1; FIG. 4Aillustrating the compressible ring before being compressed and FIG. 4Billustrating the compressible ring compressed;

FIGS. 4C-4D are cross-sections taken respectively along line 4C-4C onFIG. 4A and along line 4D-4D on FIG. 4B;

FIGS. 5A and 5B are isolated radial cross-sections of the assembly of aprofiled bar and a support ring assembly according to a secondillustrative embodiment of the present invention; FIG. 5A illustratingthe compressible insert before being compressed and FIG. 5B illustratingthe compressible insert compressed;

FIGS. 6A and 6B are isolated radial cross-sections of the assembly of aprofiled bar and a support ring assembly according to a thirdillustrative embodiment of the present invention; FIG. 6A illustratingthe compressible insert before being compressed and FIG. 6B illustratingthe compressible insert compressed;

FIG. 7 is a perspective partly sectional view of a demountable screenbasket according to a fourth illustrated embodiment of the presentinvention;

FIG. 8 is a perspective partly sectional view of a screen basketaccording to a fifth illustrated embodiment of the present invention;

FIGS. 9A and 9B are isolated radial cross-sections of the assembly of aprofiled bar and a support ring assembly of the screen basket from FIG.8; FIG. 9A illustrating the compressible inserts before being compressedand FIG. 9B illustrating the compressible inserts compressed;

FIGS. 10A and 10B are isolated radial cross-sections of the assembly ofa profiled bar and a support ring assembly of a screen basket accordingto a sixth illustrated embodiment of the present invention; FIG. 10Aillustrating the open ring opened and FIG. 10B illustrating the openring closed;

FIGS. 10C and 10D are isolated top-plan cross-sections of the assemblythe support ring assembly from FIGS. 10A-10B with profiled bars; FIG.10C illustrating the open ring opened and FIG. 10D illustrating the openring closed;

FIGS. 11 to 13 are top-plan cross-sections illustrating back contoursfor the locking portions and for the corresponding complementary groovesof the support ring assemblies of screen baskets according to seven,eight and ninth illustrative embodiments of the present invention;

FIGS. 14A-14B are partial top plan cross-sections of a clampingmechanism for a screen basket according to a tenth illustratedembodiment of the present invention; FIG. 14A illustrating the clampingmechanism in a mounting position; FIG. 14B illustrating the clampingmechanism in a pressed position; and

FIGS. 15A-15B are partial side cross-sections of the clamping mechanismfrom FIGS. 14A-14B; FIG. 15A illustrating the clamping mechanism in amounting position; FIG. 15B illustrating the clamping mechanism in apressed position.

DETAILED DESCRIPTION

In the following detailed description, same or corresponding elementsare generally indicated by same reference numerals. It is to beunderstood that other embodiments may be utilized and structural orlogical changes may be made without departing from the scope of thepresent invention. Therefore, the following detailed description is notto be taken in a limiting sense, and the scope of the present inventionis defined by the appended claims and their equivalents.

Turning now to FIGS. 1-3 of the appended drawings, a demountable screenbasket 10 according to a first illustrated embodiment of the presentinvention will be described.

The demountable screen basket 10 comprises a plurality of profiled bars12 aligned along a longitudinal axis 14 and positioned so as to define aslotted cylindrical wall 15 having an inner side 16, defining ascreening surface, and an outer side 18 both extending between twolongitudinal ends 20, a plurality of support ring assemblies 22 and 22′mounted to the plurality of profiled bars 12 transversally therefrom forassembling the plurality of profiled bars 12 into the slottedcylindrical walls 15, a pair of annular end flanges 24, each forreceiving a respective end 20 of the plurality of profiled bars 12, anda plurality of clamping posts 26 secured to both annular flanges 24 forcompressing the support ring assemblies 22.

As can be better seen from FIG. 3, each profiled bar 12 has a profiledportion 28 and a tapered locking portion 30 joined at an intermediatecross-section 32. Turning briefly to FIG. 4C, the tapered lockingportion 30 has two angled faces 31 extending from an outer face 33,thereby defining a dovetail.

Each support ring assembly 22 includes a stack of first and secondidentical support rings 34 provided with equi-distanced grooves 36configured for complementary receiving the tapered locking portion 30 ofa profiled bar 12. Since the locking portions 30 are tapered, theprofiled bars 12 are prevented from being released radially. Eachprofiled bar 12 is however slidable along the support ring assemblies 22and therefore removably mounted thereto.

The grooves 36 are located on the inner side diameter of the rings 34for outward flow screen basket configuration, such as screen basket 10.For inward flow screen basket configuration (not illustrated), thegrooves 36 are located on the outer side diameter of the rings 34, andthe clamping posts 26 are positioned on the inner side of the basket.

It should be noted that the rings 34 are manufactured before assemblyand already include the assembly grooves 36.

To ease the mounting of the profiled bars 12 into the grooves 36, thelocking portions 30 and grooves 36 are dimensioned as to yield aclearance. However, this clearance may result in slight movementsbetween the profiled bars 12 and the support ring assemblies 22 and 22′when the screen basket 10 is under stress.

As will now be described in more detail, the screen basket 10 includesmeans to bias the locking portions 30 of the profiled bars 12 towardsrespective contours of the grooves 36 so as to lock the profiled bars 12therein for applications wherein relative movements of the profiled bars12 and support ring assemblies 22 can be detrimental.

The screen basket 10, as well as any screen basket from the presentinvention, can be used in a screening apparatus either held fixed or putin constant or intermittent rotation along axis 14, or put underconstant or intermittent vibration or displacement.

With reference to FIG. 3, each support ring assembly 22 includes acompressible insert, in the form of an elastomer ring 38 mounted betweenthe two rings 34, adjacent to the locking portions 30 of the profiledbars 28.

As can be seen from FIGS. 4A and 4C, the elastomer ring 38, which has acircular cross-section, is initially positioned between the two supportrings 34 and around the circumference defined by the profiled bars 12,after the mounting of the profiled bars 12 into the ring grooves 36.Then, the two rings 34 are pressed together axially, forcing the insert38 towards the profiled bars 12 as illustrated in FIGS. 4B and 4D. Thisforces the locking portions 30 of the profiled bars 12 towards thegrooves 36, eliminating the above-mentioned clearance, thereby lockingthe profiled bars 12 into the grooves 36 as discussed hereinabove.

Even though the elastomer ring 38 is illustrated as having a circularcross section, an elastomer ring having other another regular orirregular cross-section, including for example a rectangularcross-section, can also be provided.

Now referring to FIG. 2, to press the stack of support rings 34, eachpair of rings 34 are clamped together at preferably equally spacedcircumferential locations by the clamping posts 26. The clamping posts26 are in the form of combs 26 provided with longitudinal notches 40 forreceiving the pair of rings 34. More specifically, the notches 40 aretapered to thereby axially compressing the pair of rings 34 when theyare inserted therein as shown in FIG. 2.

Even though, the clamping combs 26 are illustrated as V or U-shapedelongated members, they can also be tubular for example. The clampingcombs 26 can further be in the form of elongated beam-like membersprovided with V-shaped brackets (not shown) mounted thereon forreceiving the support ring assemblies 22.

The notches 40 are distributed to locate the support ring assemblies 22at desired locations along the basket length with uniform or variablespacing, to have for example tighter ring pair spacing in a morecritical region of the basket 10.

The clamping combs 26 are secured to the end flanges 24 via mountingrods 42.

More specifically, the annular end flanges 24 and the rings 34 areprovided with respective co-axial holes 44 and 46 for receiving the rods42. The rods 42 are provided with longitudinal threaded ends forsecuring directly into holes in one of the two flanges 22 and forreceiving a nut 48 through respective counterbores at the other end.Other means can also be used to removably secure the rods 42 to theflanges 24.

Also, the clamping combs 26 can alternatively be positioned so as toshow an angle with both the support ring assemblies 22 and 22′ and theprofiled bars 12 and are thus not limited to the position aligned withthe profiled bars 12 illustrated for example in FIGS. 1-2.

Still referring to FIG. 2, each of the end support ring assemblies 22′,which are mounted at each of the longitudinal end of the clamping combs34 so as to abut the flanges 24, include a first grooved ring 34contacting the combs 26 and a non-grooved ring 50, having a largerinside diameter than the first grooved ring 34, contacting a respectiveflange 24. A compressible insert 38 is provided between the non-groovedring 50 and the circumference created by the locking portions 30 of theprofiled bars 12 for biasing the bars 12 into the grooves of the rings34 of the assembly 22′, the face of the flange 24 contacting the insidering 50 acting as a second support ring for compressing onto the insert38.

The thickness of the non-grooved ring 50 is selected so that it issmaller than the uncompressed insert 38.

Each of the two end flanges 24 includes a recess 54 on its peripheralinner side for respectively receiving the first and second longitudinalends 20 of the profiled bars.

An illustrated method of assembling the basket 10 includes:

-   -   Inserting the profiled bars 12 into the grooves of the support        ring assemblies 22-22′;    -   Inserting the inserts 38 within the support ring assemblies        22-22′;    -   Installing the clamping combs 26 onto the support ring        assemblies 22-22′ in line with the holes 46;    -   While the clamping combs 26 are maintained in place, inserting        the rods 42 into the holes 46, thereby locking the combs 26 in        place; and    -   Securing the end flanges 24 as described hereinabove.

Other method of assembling the basket 10 can also be used.

A person skilled in the art will appreciate that the basket 10 iscompletely demountable. Therefore, when worn or broken components of thebasket 10 need to be replaced, the basket 10 can be disassembled so asto remove these components and reuse the other, still usable,components.

It has been found that any elastomeric material having a Young's moduluslower than about 20 GPa is suitable to be used as the insert.

Even though the basket 10 is illustrated with equally distanced clampingcombs 26, a screen basket according to the present invention can beprovided with unequally spaced clamping combs 26.

Also, the number of profiled bars 12, support ring assemblies 22 and/or22′, and clamping combs 26 may vary.

Furthermore, even though the screen basket 10 has been described as ascreen suitable for outward flow, it is believed to be within the reachof a person skilled in the art to adapt the present teaching for aninward flow application. For example, in such a case, the support ringassemblies 22 and 22′ and the clamping combs 26 are positioned on theinner side of the cylinder formed by the profiled bars 12, with theprofiled portions thereof located on the outside of the cylinder.

Also, the support ring assemblies can take many forms. FIGS. 5A-5Billustrates a support ring assembly 56 according to a second illustratedembodiment of the present invention. Since the support ring assembly 56is similar to the support ring assembly 22, and for concision purposes,only the differences between the two assemblies 56 and 22 will bedescribed herein in more detail. The compressible insert 58 is in theform of a wide ring having a rectangular cross-section and a widthsimilar to the width of the rings 34. Again, the insert 58 is forcedagainst the profiled bars 12 when the two metallic rings 34 are pressedtogether.

FIGS. 6A-6B illustrates a support ring assembly 60 according to a thirdillustrated embodiment of the present invention. Since the support ringassembly 60 is similar to the support ring assembly 22, and forconcision purposes, only the differences between these two assemblies 60and 22 will be described herein in more detail. The support ringassembly 60 includes a compressible insert 62 in the form of a narrowring having a width preferably smaller than the width of the metallicrings 34 and characterized by a thickness at rest. The assembly 60further includes an intermediate ring 64 positioned between the supportrings 34 and having a thickness smaller than the insert 62 thickness atrest. The insert 62 is forced against the profiled bars 12 when thestack of metallic rings 34 and 64 is axially compressed.

Turning now to FIG. 7 of the appended drawings, a demountable screenbasket 66 according to a fourth illustrative embodiment of the presentinvention will be described. Since the screen basket 66 is very similarto the screen basket 10, and for concision purposes, only thedifferences between the two screen baskets 10 and 66 will be describedherein in more detail.

The screen basket 66 further includes fasteners 68 for pressing the tworings 34 together axially and then forcing the insert 38 towards theprofiled bars 12 as illustrated in FIGS. 4B and 4D. The fasteners 68 cantake any form including rivets, bolts, clips, etc.

The use of such fasteners 68 allows limiting the number of clampingcombs 26 and rods 42.

A screen basket 70 according to a fifth illustrative embodiment of thepresent invention will now be described with reference to FIGS. 8 and9A-9B. Since the screen basket 70 is very similar to the screen basket10, and for concision purposes, only the differences between the baskets10 and 70 will be described in more detail. As will now become moreapparent, the main difference between the two baskets 10 and 70 is thesupport ring assemblies 72 of the screen basket 70 which differ from thesupport ring assemblies 22.

Each support ring assembly 72 includes first and second integral rings74 which, similarly to the rings 34 of the basket 10, extend along allthe periphery of the basket 10, and an intermediary grooved disk 76,which is made of a plurality of angular segments 78, mounted between thefirst and second rings 74.

The grooved disk 76 includes grooves 36 for complementary receiving thelocking portions 30 of the profiled bars 12 as discussed hereinbelow inmore detail.

The support ring assembly 72 further comprises two compressible insertsin the form of rings 38 positioned between a respective support ring 74and grooved disk 76 adjacent to the profiled bars 12. The inner side ofeach support ring 74 is provided with a chamfer 80 for biasing theinserts 38 towards profiled bars 12 when the support ring assembly 72 iscompressed as illustrated in FIG. 9B. Also, as illustrated in FIG. 9B,the support ring assembly 72 allows forcing the locking portion of thebars 12 towards the grooves 36, providing the locking effect discussedin further detail hereinabove.

Of course, the support rings 74 and intermediary ring 76 are providedwith holes 82, similar to holes 46 of the basket 10, for securing therods 42. To provide better stability, the holes 46 are positioned sothat each segment 78 includes at least one hole and therefore receivesat least one rod 42. Moreover, the joints 84 between two segments 78 arepreferably offset for two adjacent support ring assemblies 72.

The use of a grooved disk 76 made of segments 78 allows minimizing thelost of material. For example, when only a portion of the disk 76 isdamaged, only the corresponding segments can be changed.

The number of sections 78 forming the grooved disk 76 may of coursevary. Typically, 6 angular segments 78 are used.

Turning now to FIGS. 10A-10D, a support ring assembly 86 for a screenbasket according to a sixth illustrative embodiment of the present willnow be described. Since the support ring assembly 86 is very similar tothe support ring assembly 72, only the differences between these twoassemblies, relating mainly to the support ring assembly, will befurther described herein.

Instead of compressible inserts, such as the elastomer rings 38, thesupport ring assembly 72 includes open rings 88, having a triangularcross-section for respective complementary insertion in the chamfers 80.

As illustrated in FIG. 10C, the rings 88 are sized so as to yield a gap92 between its two extremities 90 when no pressure is exerted onto thetwo exterior support rings 74. However, when such a pressure is exertedonto the support rings 74 (see arrow 94 in FIG. 10C), its diametershrinks, as allowed by the gap 92, bringing the two extremities 90towards each other (see arrows 96) and immobilizing the locking portionof the bars 12 into the grooves 36.

The open rings 88 can be made for example of metal.

It is to be noted that the rings 88 can be replaced by any othersuitable elements or materials which expand in a confined space.

FIGS. 11 to 13 illustrate examples of back contours for the lockingportions and for the corresponding complementary grooves of the supportring assemblies of screen baskets according to seven, eight and ninthillustrative embodiments of the present invention. In all three cases,since the grooves contours are complementary to the locking portioncontours and therefore identical in shape, only the locking portioncontours will be described herein in more detail.

FIG. 11 shows a first alternate configuration of locking portions 98characterized by having an outer or abutting face 100, a first face 102extending generally perpendicularly from the outer face 100, and asecond face 104 opposite the first face 102, extending at an angledtherefrom.

FIG. 12 illustrates locking portions 106 having multiple teeth 108 onboth sides. FIG. 13 illustrates locking portions 110 with multiple teeth112 on a single side, the other opposite side 114 being generallyplanar.

FIGS. 14A-14B and 15A-15B illustrate a clamping mechanism 116 accordingto a tenth illustrated embodiment of a screen basket of the presentinvention. Since the screen basket according to this tenth illustratedembodiment is very similar to the screen basket according to the secondillustrated embodiment (see FIGS. 5A-5B), and for concision purposes,only the differences between these two embodiments will be describedherein in more detail.

The clamping bar 116 includes sequentially alternating integral narrowportions 118 and wide portions 120.

As illustrated in FIGS. 15A and 15B, the narrow portions 118 have aheight slightly less than the overall thickness of the two support rings34 with the insert 58 when the support ring assembly 56 formed therebyis not compressed (see FIG. 15A) and generally corresponding to theoverall thickness of the support ring assembly 56 when it is compressed(see FIG. 15B).

Each wide portion 120 has a height generally corresponding to theinter-space between two adjacent support ring assemblies 56.

Elongated holes 122 are provided in both the support rings 34 andinserts 58 at generally equally distanced circumferential position toreceive the plurality of clamping posts 116.

As illustrated in FIGS. 14A and 15A, the elongated holes 122 areconfigured and sized to receive the posts 116 when the posts areoriented along the elongated side of the holes 122.

As illustrated in FIGS. 14B and 15B, the clamping posts 116 are thenrotated 90 degrees from mounting position to obtain a pressed position(see arrows 124 on FIG. 14B). This rotation forces the wide portions 120to engage over the support ring assemblies 56, thereby exerting a forceonto the support ring assemblies 56 (see arrows 126). While in thispressed position, the support ring assemblies 56 are thereforecompressed, yielding the locking effect described hereinabove in moredetail.

The clamping post 116 can then be removably secured to the end flanges(not illustrated).

The present invention is not limited to a screen basket having supportdisk assemblies provided with two (2) or three (3) support rings. Forexample, four, or more rings pressed together with deformable insertsplaced between some of those rings to obtain stronger joints can beprovided. It is also possible for example to use a single support ringlocated at a certain distance in between two ring pairs. One or morerings could also be added to a ring pair without adding supplementarycompressible insert.

A screen basket according to the present invention can be provided withprofiled bars, support ring assemblies or support conforming to anyshape or contour and clamping posts so configured and sized as to yielda screening surface which is flat, curved, stepped, conical, etc.

A screen basket having different combinations of aspects of the aboveillustrated embodiments can also be provided according to the presentinvention.

Even though the screen baskets according to the illustrated embodimentsare all completely demountable, it is believed to be within the reach ofa person skilled in the art to modify one of the illustrated screenbaskets and/or use the above teaching to provide a screen basket whichis only partly demountable so as to recycle only parts of its componentsfor example.

Although the present invention has been described hereinabove by way ofillustrated embodiments thereof, it can be modified without departingfrom the spirit and nature of the subject invention, as defined in theappended claims.

1. A screen basket comprising: a plurality of profiled bars generallyaligned along a longitudinal axis so as to define a slotted cylindricalwall having an inner side and an outer side extending between twolongitudinal ends; each of the profiled bars having a radial profiledportion and a radial locking portion joined at an intermediatecross-section; the radial locking portion having an irregularcross-section including at least one radial cross-section wider than theintermediate cross-section; and a plurality of support ring assemblies,each removably mounted to at least some of the plurality of profiledbars substantially transversally therefrom for assembling the pluralityof profiled bars into the slotted cylindrical wall; each of theplurality of support ring assemblies including a stack of first andsecond support rings; at least one of the first and second support ringsincluding a plurality of grooves; each groove being configured and sizedfor complementary receiving the radial locking portion of a respectiveone of the profiled bars; the first and second support rings beingmounted to each other and to the plurality of profiled bars so as toyield a locking force towards the radial locking portion of the profiledbars, thereby locking the profiled bars thereonto.
 2. A screen basket asrecited in claim 1, wherein each of the grooves has a contour; thelocking force biasing the locking portions of the plurality of profiledbars towards the contours of the grooves.
 3. A screen basket as recitedin claim 2, further comprising means for compressing the stack of thefirst and second support rings; at least one of the support ringassemblies further comprising at least one deformable insert mountedbetween the first and second support ring adjacent the locking portionsof the profiles bars; whereby, compressing the stack causes the at leastone deformable insert to deform and to be forced radially towards thelocking portions of the profiled bars, thereby providing the lockingforce to bias the locking portions of the plurality of profiled barstowards the contours of the grooves.
 4. A screen basket as recited inclaim 3, wherein the at least one deformable insert is a compressibleinsert.
 5. A screen basket as recited in claim 4, wherein thecompressible insert is in the form of an integral ring.
 6. (canceled) 7.(canceled)
 8. (canceled)
 9. (canceled)
 10. A screen basket as recited inclaim 3, wherein at least one of the support ring assemblies furthercomprising an intermediary non-grooved ring mounted between the firstand second support rings, having a larger inside diameter than the firstand second support rings and having a thickness; the at least onedeformable insert being in the form of a compressible ring characterizedby an uncompressed longitudinal width greater than the intermediarynon-grooved ring thickness.
 11. A screen basket as recited in claim 3,wherein the deformable insert is in the form of an open ring; whereincompressing the stack causes the open ring to close and to be forcedradially towards the locking portions of the profiled bars.
 12. A screenbasket as recited in claim 11, wherein at least one of the first andsecond support rings has an edge adjacent the plurality of profiled barsprovided with a chamfer for receiving the open ring.
 13. A screen basketas recited in claim 3, wherein the means for compressing the stack ofthe first and second support rings includes at least one clamping postfor clamping the plurality of support ring assemblies.
 14. A screenbasket as recited in claim 13, wherein the at least one clamping post isin the form of a clamping comb provided with longitudinal notches forreceiving a respective one of the plurality of support ring assemblies.15. (canceled)
 16. (canceled)
 17. (canceled)
 18. A screen basket asrecited in claim 13, wherein each support ring assembly has a firstthickness when said each support ring assembly is not compressed; the atleast one clamping post including sequentially alternating narrow andwide portions; each narrow portion having a first height which isslightly less than the first thickness when the first support ringassembly is uncompressed and generally equal to the first thickness whenthe first support ring assembly is compressed; each wide portion havinga second height generally corresponding to a longitudinal interspacingbetween two adjacent of the support ring assemblies; each one of theplurality of support ring assemblies being provided with at least oneaperture having a wider side for allowing passage for the at least oneclamping post when the at least one clamping post has its wide portionsoriented along the wider side of the at least one aperture; whereby, inoperation, rotating the at least one clamping post of 90 degrees afterinsertion thereof in the at least one aperture causes the at least oneclamping post to engage and compress the stack of the first and secondsupport rings.
 19. (canceled)
 20. (canceled)
 21. (canceled) 22.(canceled)
 23. (canceled)
 24. (canceled)
 25. A screen basket as recitedin claim 3, wherein the stack of first and second support rings furtherincludes a third intermediary ring mounted between the first and secondsupport rings; the at least one deformable insert including a firstdeformable insert mounted between the first and intermediary rings andadjacent to the locking portions of the profiled bars and a seconddeformable insert mounted between the second and intermediary ringsadjacent to the locking portions of the profiled bars; the intermediaryring including the plurality of grooves.
 26. A screen basket as recitedin claim 25, wherein the intermediary ring is made of a plurality ofangular segments.
 27. A screen basket as recited in claim 26, furthercomprising at least one clamping post for receiving, longitudinallyspacing and compressing the plurality of support ring assemblies.
 28. Ascreen basket as recited in claim 25, wherein each of the first andsecond support rings has a respective edge adjacent the plurality ofprofiled bars provided with a chamfer for receiving the at least onedeformable insert.
 29. A screen basket as recited in claim 3, whereinthe means for compressing the stack of the first and second supportrings includes fasteners.
 30. The use of a screen basket as recited inclaim 1 for inward flow screening, wherein the plurality of support ringassemblies are removably mounted to at least some of the plurality ofprofiled bars on the inner side of the slotted cylindrical wall definedby the plurality of profiled bars.
 31. The use of a screen basket asrecited in claim 1 for outward flow screening, wherein the plurality ofsupport ring assemblies are removably mounted to at least some of theplurality of profiled bars on the outer side of the slotted cylindricalwall defined by the plurality of profiled bars.
 32. A screen basket asrecited in claim 1, wherein the plurality of grooves are generallyequidistanced.
 33. A screen basket as recited in claim 1, wherein theradial locking portion is generally shaped like a dovetail.
 34. A screenbasket as recited in claim 1, further comprising a plurality of clampingposts for receiving and compressing the plurality of support ringassemblies.
 35. (canceled)
 36. (canceled)
 37. (canceled)
 38. (canceled)39. (canceled)
 40. A screen basket as recited in claim 1, wherein eachof the plurality of support ring assemblies are removably mounted to atleast some of the plurality of profiled bars substantially transversallytherefrom.
 41. (canceled)
 42. (canceled)
 43. A method for assembling ascreen basket comprising: providing a plurality of support ringassemblies including first and second support rings; at least one of thefirst and second support rings including a plurality of grooves;providing a plurality of profiled bars, each having a radial profiledportion and a radial locking portion joined at an intermediatecross-section; the radial locking portion having an irregularcross-section including at least one radial cross-section wider than theintermediate cross-section; the radial locking portion being configuredfor complementary insertion into one of the grooves of the first andsecond support rings; inserting the locking portions of the profiledbars into the grooves of the first and second support rings so as togenerally align the profiled bars along a longitudinal axis and todefine a slotted cylindrical wall having an inner side and an outer sideextending between two longitudinal ends; and applying a locking forcetowards the radial locking portion of the profiled bars for releasablylocking the profiled bars in the support ring assemblies.
 44. A methodas recited in claim 43, wherein applying a locking force towards theradial locking portion of the profiled bars includes insertingdeformable inserts between the first and second support rings andinstalling clamping combs onto the plurality of support ring assemblyfor receiving and compressing the plurality of support ring assemblies,thereby forcing the deformable inserts towards the locking portion ofthe profiled bars, yielding the locking force.
 45. A method as recitedin claim 44, wherein the clamping combs have longitudinal ends; themethod further comprising securing end flanges at the longitudinal endsof the clamping combs.
 46. (canceled)